Wide track automobiles such as 4-wheeled automobiles are often occupied by only a single driver. Thus, they waste space that could more efficiently be used by a larger number of smaller, more maneuverable vehicles. Two-wheeled motorcycles, in contrast, are space-efficient, relatively economical, and fun to drive. One of their enjoyable traits is their ability to tilt when negotiating a curve. Three-wheeled motorcycles, also known as trikes, tend to be wider and are perceived to be more stable than two-wheelers, but current models are somewhat difficult to drive, since the driver needs to counterbalance the centrifugal forces on the trike by properly shifting his or her weight while cornering. In addition, since they are typically unenclosed, neither two-wheeled motorcycles nor conventional trikes offer adequate protection from inclement weather or from injuries due to accidents.
Various attempts have been made to design narrow-track vehicles that combine the best features of two-wheeled motorcycles, trikes, and four-wheeled automobiles. Some of these designs have allowed the vehicles to tilt when turning, but none have been entirely satisfactory. For instance, some designs employ tilting wheels, which require motorcycle-type tires having U-shaped profiles with reduced tire contact patches relative to the width of the tires. Other designs do not shift the vehicle's center of gravity far enough in a lateral direction to maintain equilibrium as cornering forces increase. Accordingly, none of the currently available narrow track vehicles are sufficiently stable during high-speed turns.
Tilting trains have also been designed to alleviate some of the discomfort experienced by train travelers when travelling along curves. However, the designs of these trains have resulted in only marginal improvement in cornering ability.
These and other problems are addressed by this disclosure as summarized below.